2 Samuel 18:14,15 - Joseph Benson’s Commentary on the Old and New Testaments

I may not tarry thus with thee I must not lose time in contending with thee, till I let the occasion slip. And thrust them through the heart of Absalom Not through the part properly so called, (for then he would have died immediately, and there would have been no need for his soldiers to fall upon him as they afterward did, 2 Samuel 18:15,) but through the midst of his body, which did not kill him outright, but some life still remained in him. Ten young men that bare Joab's armour Who waited upon his person as general of the army; smote Absalom and slew him By Joab's command, who probably judged that there could be no safety to the king, nor peace to the kingdom, nor security to himself, and David's friends and other loyal subjects, or to any good men, if Absalom was suffered to live. For he thought that some unquiet people, who were deeply engaged in this rebellion, would soon take occasion to move new disturbances to set him on the throne, which Absalom would be very ready to encourage. Therefore, knowing that he had been guilty of several crimes which the law of God made capital, especially of committing incest with his father's concubines, and raising an unnatural rebellion against him, with a design to rob him both of his kingdom and his life; Joab did, not as David commanded, but as, he imagined, he ought to have commanded. “Thus fell,” says Delaney, “this cruel, this murderous, this incestuous parricide! and with him, twenty thousand of his rebel adherents.” So much mischief may one restless, interested man do in his country! and such ruin may his ambition bring upon it! We do not, however, intend, by these observations, to plead Joab's justification in the act of direct disobedience to his sovereign's orders, but leave the reader to form his own judgment of the matter.